scholarly journals The Inhibitory Effects of Plant Derivate Polyphenols on the Main Protease of SARS Coronavirus 2 and Their Structure–Activity Relationship

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1924
Author(s):  
Thi Thanh Hanh Nguyen ◽  
Jong-Hyun Jung ◽  
Min-Kyu Kim ◽  
Sangyong Lim ◽  
Jae-Myoung Choi ◽  
...  

The main protease (Mpro) is a major protease having an important role in viral replication of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the novel coronavirus that caused the pandemic of 2020. Here, active Mpro was obtained as a 34.5 kDa protein by overexpression in E. coli BL21 (DE3). The optimal pH and temperature of Mpro were 7.5 and 37 °C, respectively. Mpro displayed a Km value of 16 μM with Dabcyl-KTSAVLQ↓SGFRKME-Edans. Black garlic extract and 49 polyphenols were studied for their inhibitory effects on purified Mpro. The IC50 values were 137 μg/mL for black garlic extract and 9–197 μM for 15 polyphenols. The mixtures of tannic acid with puerarin, daidzein, and/or myricetin enhanced the inhibitory effects on Mpro. The structure–activity relationship of these polyphenols revealed that the hydroxyl group in C3′, C4′, C5′ in the B-ring, C3 in the C-ring, C7 in A-ring, the double bond between C2 and C3 in the C-ring, and glycosylation at C8 in the A-ring contributed to inhibitory effects of flavonoids on Mpro.

Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 5055
Author(s):  
Douglas Kemboi ◽  
Xavier Siwe-Noundou ◽  
Rui W. M. Krause ◽  
Moses K. Langat ◽  
Vuyelwa Jacqueline Tembu

Euphorbia species have a rich history of ethnomedicinal use and ethnopharmacological applications in drug discovery. This is due to the presence of a wide range of diterpenes exhibiting great structural diversity and pharmacological activities. As a result, Euphorbia diterpenes have remained the focus of drug discovery investigations from natural products. The current review documents over 350 diterpenes, isolated from Euphorbia species, their structures, classification, biosynthetic pathways, and their structure–activity relationships for the period covering 2013–2020. Among the isolated diterpenes, over 20 skeletal structures were identified. Lathyrane, jatrophane, ingenane, ingenol, and ingol were identified as the major diterpenes in most Euphorbia species. Most of the isolated diterpenes were evaluated for their cytotoxicity activities, multidrug resistance abilities, and inhibitory activities in vitro, and reported good activities with significant half-inhibitory concentration (IC50) values ranging from 10–50 µM. The lathyranes, isopimaranes, and jatrophanes diterpenes were further found to show potent inhibition of P-glycoprotein, which is known to confer drug resistance abilities in cells leading to decreased cytotoxic effects. Structure–activity relationship (SAR) studies revealed the significance of a free hydroxyl group at position C-3 in enhancing the anticancer and anti-inflammatory activities and the negative effect it has in position C-2. Esterification of this functionality, in selected diterpenes, was found to enhance these activities. Thus, Euphorbia diterpenes offer a valuable source of lead compounds that could be investigated further as potential candidates for drug discovery.


2017 ◽  
Vol 12 (12) ◽  
pp. 1934578X1701201
Author(s):  
Natalia K. Utkina ◽  
Natalia D. Pokhilo

The ABTS•+ radical cation scavenging activity of known (2-5, 9, 10) and new (6-8) 1’-hydroxyethylnaphthazarins and their products of esterification and etherification was evaluated and a structure-activity relationship was studied. It was shown, that the structure of side chains does not affect the radical scavenging activity of 1’-hydroxyethylnaphthazarins and their derivatives. The presence of methoxyl groups on the naphthazarin core slightly enhanced the antioxidant activity of compounds compared with compounds without methoxyl groups. The presence of the additional hydroxyl group on the naphthazarin moiety of isonorlomazarin (5) and its derivative (6) is essential for the activity.


2008 ◽  
Vol 29 (6) ◽  
pp. 1228-1234 ◽  
Author(s):  
E. A. Rogozin ◽  
K. W. Lee ◽  
N. J. Kang ◽  
H. Yu ◽  
M. Nomura ◽  
...  

Author(s):  
Easwaramoorthi Deivanayagam ◽  
Jayaprakash R ◽  
Aroj Kumar Sha ◽  
Hemalatha S

ABSTRACTObjective: Aim of this work is to synthesize and characterization of the hydroxyl group the hydroxyl group substituted L-phenylalanine Schiff basesto compare their predicted quantitative structure-activity relationship (QSAR) and molecular docking against Escherichia coli protein ZipA (1s1j)outcomes with the antibacterial activity and brine shrimp lethal assay (BSLA) results.Methods: The Schiff bases of L-Phenylalanine were synthesized by the simple condensation reaction using methanol, water in 2:1 ratio at reflux andwere characterized by spectral techniques. QSAR parameters of the Schiff bases were predicted using java-based online and offline tools. Moleculardocking carried through online mcule server and CLC Drug Discovery Workbench 3. Antibacterial activity and toxicity studies were conducted usingbroth dilution and brine shrimp lethal assay methods, respectively.Results: The Schiff bases fulfilled the QSAR drug-likeness parameters and showed the docking score between −6.8 and −6.0 Kcal/mol which arehigher than amoxilicillin and gentamicin like standard drugs. They also possess good inhibition for urinary tract infection causing E. coli bacteria,and minimum inhibitory concentrations (MIC) exists between 3.25 and 5.25 μg/ml. The brine shrimp lethal concentration for 50% mortality [LC50])between 58.73 and 135.6 μg/ml.Conclusion: Para, meta and 2,4 hydroxyl substituted Schiff bases exhibited good inhibition against Gram-negative E. coli bacteria at low concentrationand the MIC exists below the LC50 value. The Schiff base showed high drug score, high docking score, and low toxicity than other Schiff base. Dockingscore, high inhibition, low clogP, low MICKeywords: L-phenylalanine, Schiff base, Quantitative structure-activity relationship, Docking, Antibacterial, Lethal concentration for 50% mortality.


2012 ◽  
Vol 7 (1) ◽  
pp. 1934578X1200700 ◽  
Author(s):  
Mi Kyoung Kim ◽  
Jun Cheol Park ◽  
Youhoon Chong

The aim of this study was to investigate the role of the aromatic substituents of the curcumin scaffold on the antibacterial activity of the resulting curcumin analogues. Six curcumin analogues with different aromatic substituents were prepared and their antibacterial activities were evaluated against two Gram-positive and four Gram-negative bacteria. The structure-activity relationship study demonstrated that antibacterial activity of the curcumin analogues was critically dependent upon the aromatic hydroxyl group. Thus, hydroxycurcumin with an additional aromatic hydroxyl group on the curcumin scaffold showed antibacterial activity against all six pathogens tested and it remained effective even against ampicillin-resistant Enterobacter cloacae. Along with the previously reported antioxidative effect, the broad-spectrum antibacterial activity of the hydroxycurcumin warrants further investigation of its biological activity as well as extensive structure-activity relationship study of the curcumin analogues with various aromatic substituents.


2017 ◽  
Vol 25 (2) ◽  
pp. 779-788 ◽  
Author(s):  
Wen-Jun Jiang ◽  
Akihiro Daikonya ◽  
Mitsuyoshi Ohkawara ◽  
Takashi Nemoto ◽  
Ryusuke Noritake ◽  
...  

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